It is where the immigrants come from that matters, as well as raw numbers. Had the US allowed everyone from Eastern Europe who wanted to come here do so since 1991, and shut the immigration from South of the border, Trump would be heading for a 49-state relection win on the order of Reagan in ‘84.
OTOH, immigrants coming from cultures that do not value education, that come from the bottom half of the world IQ scale, and who have been weaned to believe that “da gubmint” owes them a living are the problem.
Spoiler alert: Regardless of whether Trump wins relection, the current demographic trends doom the USA, later on in this century, to third-world status ... though we will outlast Western Europe which will be overrun by the Mohammedans ... you can thank Teddy Kennedy and all the other now-dead Democrat legislators (and a few GOPes), as well as LBJ who voted for the ‘65 immigration law for that ...
When the USA collapses, it will take down the rest of the world with it.
We are headed for a hundred years dark age, just like the thousand year dark age of Muslims. There will be no middle class, only the government nobility and the pheasants. Just like the Soviet Union, where everyone pretended to be equal while they slowly starved.
As an example immigrants from India mostly vote democrat. Yet the same group of immigrants have the highest income, highest net worth and highest education level of any other ethnic group in USA, including ethnic Jews, ethic Chinese & Japanese, US born citizens, European immigrants etc.
Therefore I submit the real reason democrats win over immigrants is they portray a false aura of inclusiveness much more than republicans. As the immigrants get older and wiser, only then they begin transiting towards republicans.